This section provides background information related to the present disclosure which is not necessarily prior art.
Diesel fuels derived from fossil fuel crude oil sources, e.g., petroleum-based fuels, typically include several hundred compounds. The specific compounds present in the diesel fuel are dependent on the crude oil and the refinery configuration resulting in different distillation profiles. However, many of the compounds in diesel fuel have undesirable properties. For example, paraffins, which are typically present in diesel fuels refined from petroleum-based crude oils, tend to have a desirably high cetane number, but at normal ambient temperatures tend to be in the undesirable form of a wax and have a low density. Polycyclic aromatics, also typically present in petroleum-based refined diesel fuels at high concentrations, produce particulate matter when combusted.
While synthetic diesel fuels have been produced by the Fischer-Tropsch method, such synthetic diesel fuels tend to be highly paraffinic, hence waxy and of low density, resulting in reduced fuel economy and poor cold temperature operability. Fischer-Tropsch fuels also have low aromatic content, which tends to result in undesirable seal shrinkage in internal combustion engines, which can potentially cause fuel leakage and other issues. Since Fischer-Tropsch synthetic diesel fuels suffer from high freeze points (resulting in poor cold temperature performance) and low density (resulting in a fuel economy loss), Fischer-Tropsch synthetic diesel fuels are practically useful only as fuel blending components. The present disclosure provides improved synthetic diesel fuels having superior performance as primary and sole sources of fuel for compression ignition combustion engine or motors. In certain aspects, the synthetic diesel fuels can be a biofuel obtained from a renewable resource, such as biological sources like animal or vegetable materials, and are thus regarded as being more “environmentally-friendly” than petroleum-based fuels.